Dissolution of Single Crystals of Copper in Aqueous Ethylenediamine

The kinetics of the dissolution of preferentially oriented single crystal plates of 99.999% copper in stirred aqueous solutions of 10 −2 M ethylenediamine containing oxygen have been studied. The dissolution rates, which were controlled by a transport process in solution, were a function of the temperature and stirring rate of the solution, but were independent of the crystallographic orientation of the exposed metal surface. From the examination of the facets developed during the course of the reaction on crystals with low index faces, it was concluded that the order of stability of the crystal faces was (100) > (110) > (111) in this particular system. Other than anomalous faceting observed in regions thought to correspond to grain boundaries, no correlation between chemical reactivity and crystal imperfections was observed.